Conventionally, the so-called drawer system has been used as a locking mechanism of a disk device. In the drawer system, releasing operation of a locking mechanism provided on a loading mechanism is performed by oscillation-driving a locking lever through a locking lever oscillation energizing member as a power source when used in a thin-type disk device mounted (built-in or provided outside) mainly on a notebook personal computer. Also, in the system, when keeping the locking state of the locking mechanism, the locking lever is fixed by a self-attraction type solenoid so that the locking lever does not release the lock of the locking mechanism. FIG. 8 to FIG. 10 are schematic views of the configuration of a conventional disk device as described.
This type of disk device comprises a tray 4 for loading a disk 2 to be an information recording medium, and a casing 1 inside which the tray 4 is housed to be capable of being inserted/ejected. The tray 4 is housed inside the casing 1 to be movable in the upward/downward direction (see an arrow L1) with respect to the casing 1 as shown in FIG. 8. When loading or unloading the disk 2 onto/from the tray 4, the tray 4 is pulled out from the casing 1. When writing information onto the disk 2 or reading the information therefrom, the tray 4 is pushed into the casing 1 so that the tray 4 is completely set inside the casing 1. Then, a disk drive device 3 provided in the tray 4 is activated to perform writing or reading of information to/from the disk 2.
FIG. 9 shows a schematic view of the configuration of a locking mechanism A for keeping the tray 4 to be housed inside the casing 1. The main part of the locking mechanism comprises a locking pin 5 provided on the casing 1 side and a locking lever 6 provided on the tray 4 side. Further, on the tray 4 side, provided are various structural elements necessary for engaging/releasing a locking part 6a with/from the locking pin 5 by operating the locking lever 6.
The locking lever 6 having the protruded locking part 6a on the tip to be engaged with the locking pin 5, as shown in FIG. 9, is mounted on the tray 4 to be capable of oscillating with a locking lever shaft 24 being a fulcrum. Further, it is energized to oscillated in a direction where the locking part 6a is engaged with the locking pin 5, that is, in a counterclockwise direction in FIG. 9 by a locking lever oscillation energizing member 7 composed of a spring and the like.
Inversely, an ejection lever 12 for releasing the locking part 6a from the locking pin 5 by oscillating the locking lever 6 in a clockwise direction, as shown in FIG. 10, is mounted on the tray 4 to be capable of oscillating with an ejection lever shaft 25 being a fulcrum. Further, it is energized to oscillate in a direction where a pressing piece 12a of the ejection lever 12 presses the locking lever 6, that is, in a counterclockwise direction in FIG. 9, by an ejection lever oscillation energizing member 15.
A movable piece 11a is attached to the ejection lever 12 and corresponding to this, a self-attraction type solenoid 11 is fixed on the tray 4 side. The self-attraction type solenoid 11 holds the movable piece 11a by a permanent magnet (not shown). Thereby, the ejection lever 12 is kept to be in a state shown in FIG. 9, that is the state where a pressing piece 12a formed in the ejection lever 12 does not press the locking lever 6. In the state shown in FIG. 9, the locking part 6a hooks onto the locking pin 5 so that the locking mechanism A is locked.
By operating an ejection button 10 shown in FIG. 8 in the state shown in FIG. 9, the solenoid 11 is excited by a command from a control circuit (not shown) and a magnetic force repulsing the magnetic force of the permanent magnet is generated. Thus, the movable piece 11a is detached from the permanent magnet by the magnetic force of the solenoid 11, the ejection lever 12 is oscillated in a counterclockwise direction by a force applied by the ejection lever oscillation energizing member 15, and the pressing piece 12a presses the locking lever 6 thereby oscillating the locking lever 6 in a clockwise direction opposing to the force applied by the locking lever oscillation energizing member 7. As a result, the locking part 6a of the locking lever 6 is detached from the locking pin 5 thereby to release the locking state so that the tray 4 can be ejected from the casing 1. FIG. 10 shows the state where the lock is released.
As shown in FIG. 10, when the lock is released by detaching the locking lever 6 and the locking pin 5 by operating the ejection button 10 as described, the tray 4 is pressed by an ejection mechanism B comprising a tray ejection power source 8 such as a spring or the like shown in FIG. 8, a tray ejection lever 9 and the like so as to be pushed out of the casing 1 in the forward direction with respect to the casing 1, that is, in the downward direction (see an arrow L2) in FIG. 10. Then, the final step of the pull-out operation is performed by a user through grabbing a front panel 17 (see FIG. 8).
Furthermore, a mechanism for attracting the movable piece 11a to the solenoid 11 by returning the state of the ejection lever 12 shown in FIG. 10 again back to the position shown in FIG. 9 comprises a reset lever 14 mounted on the tray 4 to be capable of oscillating with a reset lever shaft 26 being a fulcrum.
The reset lever 14 is engaged with the ejection lever 12 which oscillates in a counterclockwise direction (see an arrow L3) by the energizing force from the ejection lever oscillation energizing member 15 so that it is always oscillated in a clockwise direction (see an arrow L4) by the oscillating force of the ejection lever 12 in a counterclockwise direction. Further, in the vicinity of the end portion of the reset lever 14 on the opposite side to the part where the reset lever 14 is engaged with the ejection lever 12, a reverse-doglegged bent part 14a as a part of the reset lever 14 to be in contact with the locking pin 5 is formed due to the relative position shift generated between the casing 1 and the tray 4 caused by the inserting/ejecting action of the tray 4, that is, the position shift of the reset lever 14 against the locking pin 5.
First, by pulling out the tray 4, the reset lever 14 together with the tray 4 are moved in the downward direction (the arrow L2) in FIG. 10 and the reset lever 14 is to be in the state shown in FIG. 10. By pushing the pulled-out tray 4 inside the casing 1, a guide part 14a of the reset lever 14 is pressed by the locking pin 5 so that the reset lever 14 oscillates in a counterclockwise direction (in the opposite direction to the arrow L4) in FIG. 10. Thereby, the ejection lever 12 engaged with the reset lever 14 is oscillated in a clockwise direction (in the opposite direction to the arrow L3) so that the movable piece 11a attached to the ejection lever 12 is again to be attracted to the permanent magnet of the solenoid 11.
The shapes of the reset lever 14 and the engagement the reset lever 14 and the ejection lever 12 are designed in such a manner that the ejection lever 12 overstrokes and oscillates in a clockwise direction so as to press the movable piece 11a which is in contact with the solenoid 11 further to the solenoid 11. Therefore, the movable piece 11a is surely stuck to the solenoid 11 when the movable piece 11a is attracted again to the permanent magnet of the solenoid 11. However, in the case of such a design with overstroking, there faces a problem that an excessive stress is to work on the ejection lever 12 and the reset lever 14. Thereby, it is likely to cause damages.
In order to overcome such a problem, the movable piece 11a is attached to the ejection lever 12 through a resin spring 13. Thereby, because of the resin spring 13, the movable piece 11a allows a prescribed amount of play for the ejection lever 12.
Further, in this type of disk device, it is common to have an emergency ejection lever 16 for forcibly detaching the locking lever 6 from the locking pin 5 by a manual operation in case of breakdowns of the solenoid 11 or other members and in case when ejecting the tray 4 before applying power source to the personal computer.
The emergency ejection lever 16, as shown in FIG. 9, is mounted on the tray 4 to be capable of oscillating through an emergency ejection lever shaft 28. By pressing an operation part 16a of the emergency ejection lever 16 through inserting a thin stick from a hole 17a provided on the front panel 17, the emergency ejection lever 16 is oscillated, as shown in FIG. 10, in a counterclockwise direction (see an arrow L5). Thereby, the locking lever 6 associated with the emergency ejection lever 16 is oscillated in a clockwise direction (see an arrow L6) so that the locking part 6a is forcibly detached from the locking pin 5.
The locking mechanism of a disk device comprising the locking pin 5 on the casing 1 side and the locking lever 6 and other structural elements on the tray 4 side has been described as an example. However, there is also a disk device comprising, inversely, the locking pin 5 on the tray 4 side and the locking lever 6 and other structural elements on the casing 1 side. In any case, the basic structure and operational condition are substantially the same as those described above.
There is a problem in the conventional locking mechanism of the disk device using the solenoid described above. When impact is applied to the disk device, a torque is applied to the locking lever, the ejection lever and the like by the impact or the reaction force of the impact so that the lock is released by the rotation of the lever. Particularly, the structural parts themselves such as the movable piece which is attracted to the solenoid and the ejection lever which drives the locking lever by holding the movable piece when releasing the lock have a prescribed mass. Therefore, moment is generated in the members due to the external impact. Further, if a torque sufficient to release the movable piece from the solenoid is generated in the ejection lever in a direction overcoming the attraction force of the permanent magnet of the solenoid, the lock is to be released. Thus, it causes a problem that the locking lever is detached from the locking pin so that the tray to which a disk is loaded is to be ejected from the casing unexpectedly.
On the other hand, when the locking mechanism of a disk device is designed under consideration of the impact resistance, there generates another problem of increasing the designing cost so that the price of the product is increased.